Week 3 chapters 3 lifespan considerations,
When the nurse is reviewing a list of medications taken by an 88-year-old patient, the patient says, "I get dizzy when I stand up." She also states that she has nearly fainted "a time or two" in the afternoons. Her systolic blood pressure drops 15 points when she stands up. Which type of medication may be responsible for these effects? a NSAIDs b Cardiac glycosides c Anticoagulants d Antihypertensives
d Antihypertensives
The physiologic differences in the pediatric patient compared with the adult patient affect the amount of drug needed to produce a therapeutic effect. The nurse is aware that one of the main differences is that infants have a increased protein in circulation. b fat composition lower than 0.001%. c more muscular body composition. d water composition of approximately 75%
d water composition of approximately 75%
Summarize the impact of age-related physiologic changes on the pharmacokinetic aspects of drug therapy.
-as the body ages, the functioning of several organ systems slowly declines -absorption ~gradual reduction in ability of the stomach to produce hydrochloric acid (decrease in gastric acidity; alters absorption) ~absorptive surface area of an elderly person's GI tract is often reduced = decreased absorption ~muscle tone and motor activity in the GI tract are reduced -distribution ~gradual reduction in the total body water content with aging concentration of hydrophilic drugs may be higher because they have less body water for drugs to be diluted ~decreased muscle mass; fat soluble drugs may have prolonged drug action ~reduced protein concentration in the blood, reduced number of protein-binding sites = unbound (active) drug in blood -metabolism ~metabolism and blood flow to liver both decline = prolong half life of many drugs -excretion ~renal function decline (in 2/3 of elderly) = delayed drug excretion, therefore drug accumulation
Hey Tyler is to receive a daily dose of digoxin 2 mcg/kg/ day IV. The toddler weighs 23 pound. Calculate the amount of medicine in milligrams that the toddler will receive
0.21mg
The nurse is preparing to give an oral dose of acetaminophen (Tylenol) to a child who weighs 12 kg. The dose is 15 mg/kg. How many milligrams will the nurse administer for this dose?
180mg
A toddler is to receive medication that is does as 8 mg\kilograms. The child was 40 kg. What dose of medication will the nurse administer
320 mg
Provide several examples of how age affects the absorption, distribution, metabolism, and excretion of drugs.
Absorption Despite an age-related decrease in small-bowel surface area, slowed gastric emptying, and an increase in gastric pH, changes in drug absorption tend to be clinically inconsequential for most drugs. One exception is Ca carbonate, which requires an acidic environment for optimal absorption. Age-related increases in gastric pH decrease Ca absorption and increase the risk of constipation. Thus, elderly patients should use a Ca salt (eg, Ca citrate) that dissolves more easily in a less acidic environment. Another example of altered absorption is early release of enteric-coated dosage forms with increased gastric pH. Distribution With age, body fat generally increases and total body water decreases. Increased fat increases the volume of distribution for highly lipophilic drugs (eg, diazepam, chlordiazepoxide) and may increase their elimination half-lives. Serum albumin decreases and α1-acid glycoprotein increases with age, but the clinical effect of these changes on serum drug binding is unclear. In patients with an acute disorder or malnutrition, rapid reductions in serum albumin may enhance drug effects because serum levels of unbound (free) drug may increase (only unbound drug has a pharmacologic effect). Phenytoin and warfarin are drugs with a high risk of toxic effects when serum albumin level decreases. Hepatic metabolism Overall hepatic metabolism of many drugs through the cytochrome P-450 enzyme system decreases with age. For drugs with decreased hepatic metabolism (see Effect of Aging on Metabolism* and Elimination of Some Drugs), clearance typically decreases 30 to 40%. Theoretically, maintenance drug doses should be decreased by this percentage; however, rate of drug metabolism varies greatly from person to person, and individual dose adjustment is required. Hepatic clearance of drugs metabolized by phase I reactions (oxidation, reduction, hydrolysis—see Common Substances That Interact With Cytochrome P-450 Enzymes) is more likely to be prolonged in the elderly. Usually, age does not greatly affect clearance of drugs that are metabolized by conjugation (phase II reactions). First-pass metabolism (metabolism, typically hepatic, that occurs before a drug reaches systemic circulation) is also affected by aging, decreasing by about 1%/yr after age 40. Thus, for a given oral dose, the elderly may have higher circulating drug levels. Important examples of drugs with a high risk of toxic effects include nitrates, propranolol, phenobarbital, and nifedipine. Renal elimination One of the most important pharmacokinetic changes associated with aging is decreased renal elimination of drugs. After age 30, creatinine clearance decreases an average of 8 mL/min/1.73 m2/decade; however, the age-related decrease varies substantially from person to person. Serum creatinine levels often remain within normal limits despite a decrease in GFR because the elderly generally have less muscle mass and are generally less physically active than younger adults and thus produce less creatinine. Maintenance of normal serum creatinine levels can mislead clinicians who assume those levels reflect normal kidney function. Decreases in tubular function with age parallel those in glomerular function. These changes decrease renal elimination of many drugs (see Effect of Aging on Metabolism* and Elimination of Some Drugs). Clinical implications depend on the extent that renal elimination contributes to total systemic elimination and on the drug's therapeutic index (ratio of maximum tolerated dose to minimum effective dose). Creatinine clearance (measured or estimated using computer programs or a formula, such as Cockcroft-Gault—see Evaluation of the Renal Patient : Creatinine clearance) is used to guide drug dosing. The daily dose of drugs that rely heavily on renal elimination should be lower and/or the frequency of dosing should be decreased. Because renal function is dynamic, maintenance doses of drugs may need adjustment when patients become ill or dehydrated or have recently recovered from dehydration.
Pregnancy safety category C
Adverse effects reported in the animal fetus; information for humans is not available
One year to 12 years
Child
Calculate a drug dose for a pediatric patient using the various formulas available (this will be required during your Pediatric Nursing course).
BSA = body surface area (BSA of adult % BSA of child) x adult dose =estimated child's dose BSA of child (m^2) x (manufactures recommended dose/m^2) = estimated child's dose
Most drug references provide recommend a pediatric doses based on what
Body weight in kilograms
Physiologic changes in the adult patient
Cardiovascular ⬇️ cardiac output = ⬇️ absorption and distribution ⬇️Blood flow = ⬇️ absorption Gastrointestinal ⬆️ PH = alter absorption ⬇️ peristalsis = delayed gastric emptying Hepatic ⬇️ enzyme production=⬇️ metabolism ⬇️ blood flow= ⬇️ metabolism Renal ⬇️ blood flow=⬇️ excretion ⬇️ function= ⬇️excretion ⬇️ glomerular filtration rate=⬇️ excretion
Pregnancy safety category X
Fetal abnormalities have been reported, and positive evidence of fetal risk in humans is available from animal and/or human studies. These drugs are not to be used in pregnant women.
A woman who has just discovered that she is pregnant is asking the nurse about taking medications. The nurse keeps in mind that the greatest risk for drug induced development defects occurs during what trimester of pregnancy
First
Which physiologic factor Is the most responsible for the differences in the pharmacokinetics and pharmacodynamic behavior of drugs in neonates and adults
Immaturity in neonatal organs
One month up to one year
Infant
Younger than one month
Neonate or newborn infant
The nurse recognizes that the drug dose is an older adults are based off what
One's body weight and the organ function
influences of the patient's age on the effects of the drugs and drug responses
Pediatric patient has small bodies and immature organs, they are very susceptible to drug interactions, toxicity and unusual drug responses. Pediatric patients require different dosage calculations an adults. Calculating doses is according to their body weight. Adult patients how drugs differently and are more acceptable to have an adverse effects and toxicity. The psychological changes affect the action of many drugs as a person ages. As the body ages the function of several organ systems slow. Changes in the drug molecule receptors in the body can make the patient more less sensitive to certain medication for example older adults, increase sensitivity to central nervous system depressant medication because of the reduction of the integrity of the blood brain barrier
Pregnancy safety category D
Possible fetal risk in humans has been reported; however, in selected cases consideration of the potential benefit versus risk may warrant use of these drugs in pregnant women.
Pregnancy safety category B
Studies indicate no risk to the animal fetus; information for humans is not available
Pregnancy safety category A
Studies indicate no risk to the human fetus
active transport
The active (energy-requiring) movement of a substance between different tissues via pumping mechanisms contained within cell membranes.
Explain how these age-related changes in drug pharmacokinetics influence various drug effects and drug responses across the lifespan.
The ageing process is characterized by structural and functional changes affecting all organ systems and results in reduced homeostatic capacity. Although the function of a particular system may be maintained during resting conditions, the reduction of functional reserve is responsible for an increased vulnerability to stress. Changes in body composition, hepatic and renal function are responsible for an increase in the volume of distribution of lipid soluble drugs, reduced clearance of lipid soluble and water soluble drugs, respectively. All these changes lead to a prolongation of plasma elimination half-life. Significant pharmacodynamic changes also occur which, in general, tend to increase sensitivity to drugs. The reduced functional reserve itself also leads to an increase in sensitivity by impairing homeostatic compensatory mechanisms. A better understanding of the effects of ageing on the clinical pharmacology of therapeutic agents would enhance the quality of prescribing.
Diffusion
The passive movement of molecules or particles along a concentration gradient, or from regions of higher to regions of lower concentration.
Polypharmacy
The use of many different drugs concurrently in treating a patient, who often has several health problems.
Which explanation underpins the nurse understanding that the greatest risk to the fetus to the exposure of maternal drugs occurs in the first semester
This is the period of organogenesis
The nurse is reviewing factors that influence pharmacokinetics in the neonatal patient. Which factor puts the neonatal patient at risk with regard to drug therapy? a Immature renal system b Hyperperistalsis in the GI tract c Irregular temperature regulation d Smaller circulatory capacity
a Immature renal system
. The nurse is preparing to administer an injection to a preschool-age child. Which approaches are appropriate for this age group? (Select all that apply.) a Explain to the child in advance about the injection. b Provide a brief, concrete explanation about the injection. c Encourage participation in the procedure. d Make use of magical thinking. e Provide comfort measures after the injection.
b Provide a brief, concrete explanation about the injection. d Make use of magical thinking. e Provide comfort measures after the injection.
While teaching a 76-year-old patient about the adverse effects of his medications, the nurse encourages him to keep a journal of the adverse effects he experiences. This intervention is important for the elderly patient because of which alterations in pharmacokinetics? a Increased renal excretion of protein-bound drugs b More alkaline gastric pH, resulting in more adverse effects c Decreased blood flow to the liver, resulting in altered metabolism d Less adipose tissue to store fat-soluble drugs
c Decreased blood flow to the liver, resulting in altered metabolism
. A pregnant patient who is at 32 weeks' gestation has a cold and calls the office to ask about taking an over-the-counter medication that is rated as pregnancy category A. Which answer by the nurse is correct? a "This drug causes problems in the human fetus, so you should not take this medication." b "This drug may cause problems in the human fetus, but nothing has been proven in clinical trials. It is best not to take this medication." c "This drug has not caused problems in animals, but no testing has been done in humans. It is probably safe to take." d "Studies indicate that there is no risk to the human fetus, so it is okay to take this medication as directed if you need it."
d "Studies indicate that there is no risk to the human fetus, so it is okay to take this medication as directed if you need it."
pediatric
pertaining to a person who is 12 years of age or younger
older adults
pertaining to a person who is 65 years of age or older
neonate
pertaining to a person younger than one month of age; newborn infant
Identify drug related concerns during pregnancy and lactation and for a bite and explanation of the psychological basis for these concerns
pregnancy -the fetus is exposed to the same drugs as the mother -first trimester of pregnancy is general the period of greatest danger of drug-induced developmental defects -drug therapy during pregnancy can be broken down into three areas: drug properties (dosage, chemistry, and administration), fetal gestational age (most risk 1st trimester; age also determines when a drug can most easily cross the placenta to the fetus) and material factors (mother's physiology can affect the amount of drug to which the fetus may be exposed) lactation -a wide variety of drugs easily cross from the mother's circulation into the breast milk and subsequently to the infant -the drug characteristics that increase the likelihood of drug transfer via breastfeeding include fat solubility, low muscular weight, non ionization and high concentration
younger than 38 weeks gestation
premature or preterm infant
Identify the importance of a body surface area (BSA) nomogram for drug calculations in pediatric patients.
you need the child's BSA nomogram (height and weight) to find the proportion equal to adults to plug into the equation and find the correct drug dosage for child
